Surge / Ground / Lightning

[bud--]

----------------------------

----------------------------------------
Your point is true- the time interval is so small that for practical
purposes it can be ignored. I am not denying that. Obviously I gave that
impression- sorry for that.

I was simply pointing out that phil had it right in theory and Tony had it
wrong.

After this time for the wave to travel to the end and be reflected (and
other re-reflections die out) then conventional circuit theory is
applicable. The fact that the time is extremely small simply means that we
can pretend that it doesn't even exist.

While Matzloff is right in the time for a round trip is of the order of
200m, it is also dangerous to assume that one can ignore waves for shorter
distances. For example, a stroke to a tower of an EHV line (a lot less than
200m) will go down the tower, meet ground resistance and be reflected.
Such reflections have been found to be more likely to cause flashover than
direct strokes to the line (EPRI). Similarly, the practice in substations
is not "whole station" protection (where this is applicable, it must be done
considering a number of factors- quite interesting ) and putting specific
protection as near as possible to the protected apparatus-definitely within,
say, 10m. - It's not just the time to peak that is the critical factor. Do a
lattice diagram approach or use Bergeron's method (Hermann Dommel did a lot
of work with this at EPRI and has a lot of papers in IEEE- more dealing with
switching surges than lightning).
It's been a long time since I did any calculations in this area so I would
have to brush up.

I am real glad the probability of a direct house strike is low. I have
some appreciation for the earthing/bonding required in a substation
(also referred to by nobody).

Now - is this all germane to household protection? You say not and I agree
with you- because household equipment can ride through - at worst- doubling
of the clamped voltage for a very short time even though the clamped voltage
is relatively small compared to the peak of the incoming surge. --

The effect Martzloff was specifically looking for in experiments was
doubling of voltage.

As an aside, several of the experiments done by Martzloff were at EPRI.

 

[Guest]

| (e-mail address removed) wrote:
|> | (e-mail address removed) wrote:
|>
|> |> | w_' professional engineer source says 8 micoseconds with most of the
|> |> | spectrum under 100kHz.
|> |>
|> |> Even with 1 nanosecond rise time, most of the energy will be present in
|> |> the spectrum below 100 kHz. That means nothing when the surge is strong
|> |> enough to have energy above some frequency that is relevant to the whole
|> |> system involved that can do damage. That frequency might be 100 Mhz for
|> |> some thing, and 1 GHz for other things.
|> |
|> | Still missing - your source. Nanosecond risetime. 100MHz spectrum.
|>
|> Observation. Of course this is a concept you cannot understand.
|
| Observation proves flying saucers and magic.
|
| Without supporting sources it is Phil's Phantasy Physics.
| Where is a source that supports your belief in nanosecond risetimes and
| 100MHz spectrum?

Since you seem unwilling to just discuss technical aspects of things, I have
to conclude that you simply do not understand what it is you read and quote.
Too many times you quote out of context. I don't know where that is because
you are trying to be manipulative or simply on account of ignorance. There
is that old sayind "Do not ascribe to malice that which can be explained by
ignorance". I don't know if I should follow it's advice.

There is no point in spending the effort to find some quotable source because
you wouldn't know what to do with it. How could you possibly comprehend what
I would give you if you can't even comprehend what you post.

After this round of followups, I'm done with this thread and I'm done replying
to you. If curing your ignorance is in your future, it will have to be from
someone else.

 

[Guest]

| I can attest to vhf/uhf content in lightning strikes. I worked for a
| communications outfit. We owned and maintained a number of comm sites
| with towers and antennas. One strike on an antenna destroyed the LDF rf
| cable all the way to the polyphaser at the bottom of the tower. It had
| blowouts at about 1 foot intervals all down it's length suggesting a
| 1/2 wave of about 1 foot or approx 460 mhz. That's one hell of a lot of
| energy at that frequency..

Apparently you had some kind of resonance involved. Maybe the antenna itself
can cause that. Or the output tank circuit in the transmitter. Once you have
the resonance to narrowband the energy, it would only take a reflection back
up the line and you turn a propogating surge into standing waves.

 

[bud--]

But when a plug-in protector is sold to maximize
profits (not for protection), then grossly undersized protectors also
create another problem - scary pictures:
http://www.hanford.gov/rl/?page=556&parent=554

w_ can't understand his own hanford link. It is about "some older
model" power strips and says overheating was fixed with a revision to
UL1449 that required thermal disconnects. That was 1998. There is no
reason to believe, from any of these links, that there is a problem with
suppressors produced under the UL standard that has been in effect since
1998.
But with no valid technical arguments all w_ has is pathetic scare tactics.

For reliable information on surges and protection read the IEEE and NIST
guides. (Both say plug-in suppressors are effective.)

 

[Guest]

| (e-mail address removed) wrote:
|>
|> | Now - is this all germane to household protection? You say not and I agree
|> | with you- because household equipment can ride through - at worst- doubling
|> | of the clamped voltage for a very short time even though the clamped voltage
|> | is relatively small compared to the peak of the incoming surge. --
|>
|> My belief is that they
|> can, and will at times.
|
| People believe in flying saucers.
| Where is a source that supports your belief?

My observations support my belief. I don't expect YOU to believe it on the
basis if MY observations, as I certainly won't believe things on the basis
of YOUR observations. What I am posting about is for you to UNDERSTAND what
I believe, not that you have to believe it. Maybe someday you will come to
understand it, and then you might realize how you have misread what it is
you have been quoting online.

Since you spend all your keystrokes making person attacks or insisting on
something being cited, or make quotes that are often truncated incorrectly
or misapplied, I can only conclude you have no actual understanding of what
it is you have been quoting. What good would me citing anything do for you
if you can't understand it.


|> I do agree that things can survive at the clamping voltage. But there has to
|> be a clamping situation. It's too easy for a surge to come in as a common
|> mode surge where the voltage difference across the MOVs would be (nearly) zero.
|> Then all we have is a propogating wavefront. And if it is strong and/or close
|> then we have very fast rise times. And it passes by the MOVs "laterally".
|
| Where is a source that supports your belief in nanosecond risetimes and
| 100MHz spectrum?

Another poster followed up to my post you just followed up to that also has
experienced the same thing. That might not be some published citation that
you want. But that doesn't matter. It seems you can't comprehend what this
is about regardless of whether it is observed by others, or yourself, or by
the experts you cite.


|> But one thing I do see in at least part of this thread is that Bud
|> focuses on quoting things other people say, and does very little to express
|> things in his own words.
|
| I focus on the real world. You focus on your beliefs.

You focus on citing and quoting things you do not understand well enough to
just talking about them in technical terms.


| Where is a source that supports your belief in nanosecond risetimes and
| 100MHz spectrum?

See above.

And after this round of followups, I'm done with this thread and with your
posts on this subject. You can have the last say, but I will not even read
it.

 

[trader4]

In alt.engineering.electrical (e-mail address removed) wrote:

| On May 5, 1:44?am, (e-mail address removed) wrote:
|>
|>
|> |> ||> |> |
|> |> |>
|> |> |> The MOVs will act like conductors when they are clamping. ?The surge will
|> |> |> take both paths ... the path through the MOVs, and the path goingpast the
|> |> |> MOVs. ?In general, about 50% will go each way. ?That can vary at higher
|> |> |> frequencies.
|> |> |
|> |> | Why would you assume that 50% will go each way when you don't knowthe
|> |> | impedance of each direction? ?When conducting, or at failure, the MOV has a
|> |> | very low impedance.
|> |>
|> |> There is a distinction between "go each way" and "what comes back" due to
|> |> the impedance. ?It will be about 50% that goes each way _because_ the power
|> |> itself does not (yet) know the impedance (at a distance), until it gets
|> |> there.
|> |
|> | Another installment of Phil's Phantasy Physics using transmission line
|> | theory.
|>
|> Not understanding it is your loss.
|
|
| I have to agree that this is Phantasy Physics.    We're supposed to
| believe that a surge reaching a MOV is going to split 50-50, with half
| of it going to the MOV path and half moving on down the line,
| reagrdless of the impedance of the two paths?    That would render all
| surge protection about 50% effective.

You did not read very carefully.  The reference to 50-50 split is about the
contribution of the MOVs themselves.  That is an essential understandingof
the components so the whole system can be figured out.  The impedance down
the paths is another separate component, which also has to be figured in
when determining the whole picture.

You have confused a component with the entire system.  You need to read more
carefully.  Or you need to understand the distinction of individual components
as they apply to the whole system

The whole wiring system is extrememly complex.  It cannot be understood
properly without first understanding the components.  And that includes
understanding that MOVs, when they conduct, do look to the propogating
energy as two paths to go down, and it will (initially) go both ways in
about an equal amount.

Maybe you should review what you actually stated in the context of
current surge supression discussion:
"
"The MOVs will act like conductors when they are clamping. The surge
will
|> |> take both paths ... the path through the MOVs, and the path
going past the
|> |> MOVs. In general, about 50% will go each way. That can vary at
higher
|> |> frequencies. "

That sure sounds like 50% of the surge is going through the MOV and
the other 50% is going on past it to the protected equipment.

And that I would have to agree with Bud on, it's phantasy physics,
because if it were true, no type of surge protection would work,
because it would only be 50% effective.

 

[Sjouke Burry]

What kind of ground rods? I prefer steel core, copper clad ones I even
have the special heavy hammer>

Can you trim W_tom with that?? Or is he incurable?

 

[trader4]

   Where did I say HOW was protected? It was my second week at that
station, and the chief engineer took off on a long overdue vacation. If
you would learn to read, rather than just do mindless rants you wouldn't
look so stupid.  At that time the building had a UFER ground, and a
three phase protection system at the meter CTs. That didn't prevent the
damage, as you claim it should.


   Sorry, _wacko_ but you are the one slinging insults and ignoring
proof from hundreds of people.


   Gee, _wacko_ you've never seen ANY modern business telephone
equipment?  Gas tubes are fragile and very expensive. The protection
isn't to save the privately owned telephones, it it to limit damage to
the building.  Even that mid '60s 1A2 system had every output of the
power supply fused to prevent a fire. Explain why an MOV's capacitance
is high enough to affect a phone line. Never mind.  I have a Nitsuko/NEC
DX2NA-32SYTEMEM KEY TELEPHONE SYSTEM in front of me, and every CO line
in it has a MOV across the line.  Once more, you're preaching lies and
using deceit to try to make others look bad.

,http://refurbishednitsuko.net/productInfo.aspx?productID=75978489-9ac....>
is the Central Office line card for four telephone lines. See the black
MOVs to the right of each pair of fuses?

<http://refurbishednitsuko.net/productInfo.aspx?productID=f5453e33-047....>
is the card for four standard 2500 type telephones, or equivalent
equipment. See the pairs of black MOVs over the blue connectors at the
bottom of the screen? They are all japanese, with no brand markings.

<http://www.epcos.com/web/generator/Web/Sections/Publications/PDF/SIOV...>
is the Epcos MOV databook, with datasheets for Telecom applications.
page 213 list the TELECOM MOV data.

   Every line into that studio building had a long distance call device
diverter in the line that had MOV across the phone line. Every one of
them survived the direct hit to the building and STL tower. That's more
than can be said of your ability to use reason, and learn new things.

   You need to get your head out of 1920 and learn modern electronics.
The one thing we learned today is that you don't know any more about
Telecom that you do lightning protection, or reading comprehension.

W_ denies MOVs are commonly used in typical electonics or modern
appliances too. He had to, because he can't answer the obvious
question of how MOVs can be used effectively in these applications,
yet they can't work in plug-in protectors and the only way to get any
protection is to have a nearby direct earth ground. Faced with the
problem of MOVs providing protection in electronics/appliance without
an earthground, he simply denies MOVs are used in electronics and
appliances. Here's the references that I provvided him on that one:

Here, from Appliance Magazine and Appliance Design websites:

http://www.appliancedesign.com/CDA/Articles/Electronics/BNP_GUID_9-5-...


"New thermally enhanced MOVs help protect a wide variety of low-power
systems against damage caused by over-current, over-temperature and
over-voltage faults, including lightning strikes, electrostatic
discharge (ESD) surges, loss of neutral, incorrect input voltage and
power induction.


These devices help provide protection in a wide range of AC line
applications, including AC mains LED lighting systems, PLC network
adapters, cell-phone chargers, AC/DC power supplies (up to 30 VA as
input power for 230 VAC input voltage), modem power supplies, AC
panel
protection modules, AC power meters, and home appliances. "


http://www.appliancemagazine.com/print.php?article=1778&zone=1&first=1


"Protecting increasingly sophisticated and complex control boards
from
misconnection, power surges, or short circuit damage is of particular
concern to the equipment manufacturer. Although appliance
transformers, their enclosures, and connections are capable of
withstanding higher voltage transients, the use of sensitive solid-
state devices on the board necessitates improved overcurrent,
overtemperature, and overvoltage control.


Coordinating overcurrent and overvoltage protection can also help
designers comply with safety agency requirements, minimize component
count, and improve equipment reliability. A metal oxide varistor
(MOV)
overvoltage protection device used in a coordinated circuit-
protection
strategy with a line-voltage-rated PPTC overcurrent device helps
manufacturers meet IEC 6100-4-5, the global standard for voltage and
current test conditions for equipment connected to ac mains."

 

[Mike Tomlinson]

Martzloff has written "the impedance of the grounding
system to 'true earth' is far less important than the integrity of the
bonding of the various parts of the grounding system."

Indeed. This is an important principle of the UK wiring code. It's
referred to as "equipotential bonding." Such a concept, of course,
would be far beyond the understanding of w_'s lone brain cell.

 

[Mike Tomlinson]

Last I heard UK phone entry protectors did not clamp the voltage to
earth.

You're quite correct. It's a practice that the GPO (forerunner to
British Telecom) abandoned in the 1960s, showing how up to date w_'s
"knowledge" is.

 

[Guest]

... This is an important principle of the UK wiring code. It's
referred to as "equipotential bonding."

I wonder if "ring mains" (an extra wire from the last outlet to make
a loop back to the fusebox) are legal in the US. Seems like a nice way
to improve voltage regulation with a little extra wire, and if the ring
wire only breaks in one place, all the outlets keep working.

Nick

 

[Guest]

In alt.engineering.electrical (e-mail address removed) wrote:

|
|>... This is an important principle of the UK wiring code. It's
|>referred to as "equipotential bonding."
|
| I wonder if "ring mains" (an extra wire from the last outlet to make
| a loop back to the fusebox) are legal in the US. Seems like a nice way
| to improve voltage regulation with a little extra wire, and if the ring
| wire only breaks in one place, all the outlets keep working.

It is not legal in the US. It is also considered technically unsafe.

You could wire a ring circuit with AWG #14 CU rated at 15 amps and protect
it with a 30 amp breaker under the theory that the current would be split
across the 2 paths between the source (breaker) and the load. This is the
most unsafe configuration because if one of the wires breaks, the breaker
will not detect it, and you won't notice until a fire starts.

You could wire the same circuit to two separate 15 amps breakers. In this
case it is somewhat safer because if one wire breaks, you can't get any use
via one of the breakers, effectivly reducing the current that would trip
the circuit via the remaining breaker. This is still unsafe because the
broken wire could merely be loose, and shutting off one breaker would leave
the circuit potentially live via the other breaker as the wire could come
back in contact.

There could also be confusion with separate breakers. The breakers have to
be on the same pole (phase), an issue not present in the single pole single
phase home wiring most homes have in UK. The USA, however, has two pole
single phase wiring. One way around that would be a "tandem" breaker with
the two handles fused together.

The safest case would be wiring both ends of the ring into the same breaker
rated for the current capacity of the wire as if used in a regular branch
circuit. Even this would have a safety issue. If the wire became loose at
one point in the ring, it would still be a potential hot spot that would be
not as easily noticed as a similar loose wire in a branch circuit. That hot
spot could then start a fire.

So far I have only described issues with the hot wiring. There are issues
with the neutral wiring as well. In all the above configurations, a neutral
would have to be wired in from both ends of the ring, and each be wired in
a separate hole (not doubled up) in the neutral bus bar. A loose neutral in
all these cases would go unnoticed just like a hot wire. But in cases where
the total current available (either the 30 amp single breaker, or tandem 15
amp breakers, described above) exceeds the wiring (when neutral is AWG #14 CU)
a wiring overheating problem exists.

The grounding wire would also have to be wired correctly from both ends.

An even greater double hazard potential exists when the neutral on one end is
broken while the hot on the other end is broken (or shut off at the breaker).
This creates a large inductive loop which can energize other wiring and cause
various problems with many metallic constructions.

Very little is gained by doing this over direct branch circuits. The issue
of voltage stability is addressed by keeping branch circuits short. It is
my understanding that UK ring circuits tend to be longer and run all around
the portion of a house (often an entire floor). Branch circuits in the USA
tend to be shorter.

Very long circuits can have voltage issues. An example is a home with a 1000
foot long driveway into the property, and a string of many lights along the
way. The more distant lights would be dimmer. This can be addressed to at
least balance out the dimming by using a loop-back circuit, which is still a
branch circuit. This is a more expensive circuit that is done by having an
extra hot wire run with the circuit in the same cable or conduit. Each lamp
is connected between the extra wire and the neutral. The extra wire is then
connected to the fed hot wire at the last lamp in the string. There is no
other connected to the fed hot wire other than the last lamp and the source
controlling switch. With this loop-back circuit, each lamp has the same
circuit length, and thus will have the same voltage drop.

The above technique was discussed on electrical-contrator.net a while back,
but they have since changed web site software, and my old links do not work.

 

[Guest]

| I had a microwave oven that had a MOV across the 120V line ahead of the
| power switch. The other side of the 120/240 20A circuit supplied a
| refrigerator. The loss of the neutral applied a good part of the 240V
| across the MOV when the refrigerator attempted to start.
|
| The MOV didn't last long! It would probably have been OK on the load
| side of the switch.
|
| I know that refrigerators should be alone on a "home run" circuit, and
| neutrals shouldn't be connected with wire nuts, but that wasn't how it was!

How would you connect a neutral? Doubled up on a receptacle device screw?
The usual practice is to wire the neutral in a wire nut so it can feed the
device in that box, as well as connect up and down stream, even if the
device is removed.

OTOH, I don't like wire nuts. I've seen them come loose even when wired
together well. Maybe it was a defective nut. I definitely will try to
avoid them when my new house gets built (a lot of bad electrical things
will be avoided in it).


| My only complaint with some plug-in protectors is that the MOVs are
| often much too small. I've also seen some with only a line-line MOV.

You had a plug-in protector for a double line (240V) circuit? Or are you just
referring to the neutral as one of the lines?

I'm still on the hunt for a plug-in surge suppressor power strip for 240V
with NEMA 6-15P plug and NEMA 6-15R outlets. The MOVs between each line
and ground need to be the ones appropriate for 120V (330V clamp rated) and
the ones between the two lines appropriate for 240V (660V clamp rated).

 

[Guest]

| (e-mail address removed) wrote:
|>
|> | I can attest to vhf/uhf content in lightning strikes. I worked for a
|> | communications outfit. We owned and maintained a number of comm sites
|> | with towers and antennas. One strike on an antenna destroyed the LDF rf
|> | cable all the way to the polyphaser at the bottom of the tower. It had
|> | blowouts at about 1 foot intervals all down it's length suggesting a
|> | 1/2 wave of about 1 foot or approx 460 mhz. That's one hell of a lot of
|> | energy at that frequency..
|>
|> Apparently you had some kind of resonance involved. Maybe the antenna itself
|> can cause that. Or the output tank circuit in the transmitter. Once you have
|> the resonance to narrowband the energy, it would only take a reflection back
|> up the line and you turn a propogating surge into standing waves.
|>
| Pretty much what we determined. Also in another thread I stressed that
| the rise time by itself does not determine frequency content. One needs
| to know the rate of change, or slew rate, to determine that. A
| lightning pulse may have a rise time of 1.2 microseconds but in that
| short time the current can rise to thousands of amps, generating a large
| amount of vhf,uhf energy.

In some plots of voltage rises I've seen in the past, the rise was not at all
a smooth one. It went up in steps. Of course if one _thinks_ there will be
no VHF or UHF energy and does measurement with a ssytem only capable of lower
frequencies, that would smooth out how the rise appears.

 

[w_tom]

Can you trim W_tom with that?? Or is he incurable?

He is incurable as long as others post outright lies and myths while
denying what really provides surge protection. Now to discuss what is
relevant.

If in sand, a single ground rod is probably insufficient earthing.
For example, a FL couple suffered repeated direct lightning strikes to
their bathroom wall. They have lightning rods installed. Lightning
again struck that exterior wall. Lightning rods were earthed by 8'
ground rods only in sand. Plumbing inside that wall connected to
deeper (more conductive) limstone. Lightning found a better
connection to deeper limestone via the bathroom wall.

What will provide sufficient earthing? Without knowledge of the
underlying geology, some will expand that earthing with a buried wire
around the entire building (halo or ring ground). Others will may
install a large and interconnected network of ground rods. Do you
need that much? Expanding the earthing may be easier than learned
later it was not sufficient. Also useful is to canvas the
neighborhood to learn what others have experienced for ten or more
years.

Reducing earth resistance is not as important as creating single
point ground with a shorter connection, more conductive (impedance)
than any other path, AND creating equipotential beneath the building.
Too many assume a water pipe is better because it is longer. But a
better earth ground meets two slightly different criteria -
conductivity and equipotential. IOW some ground rods located short to
all 'whole house' protectors may be superior earthing than the water
pipe. Appreciate that wire length may be more critical than the size
of an earthing electrode.

 

[w_tom]

Indeed. This is an important principle of the UK wiring code. It's
referred to as "equipotential bonding." Such a concept, of course,
would be far beyond the understanding of w_'s lone brain cell.

UK wiring code alone does not provide sufficient earthing for
something not intended to address. Code addresses earthing for human
safety. Proper earthing for surge protection must both meet and
exceed code requirements. Essential for surge protection is that all
utilities be earthed very short to the same earthing electrode. UK
code does not require that. In fact, many UK master sockets have no
earthing connection meaning no phone line protection.

Mike Tomlinson posts insults when he does not have facts. Those who
would promote magic box plug-in protectors are same who also post
these insults. Same technique used by Rush Limbaugh to prove Saddam
had WMDs.

Single point earth ground remains essential to surge protection -
which only makes people like Mike Tomlinson post more insults. A
protector is only as effective as its earth ground. An effective
protector makes a 'less than 10 foot' connection to that earth ground
rod.

 

[w_tom]

w_ can't understand his own hanford link. It is about "some older
model" power strips and says overheating was fixed with a revision to
UL1449 that required thermal disconnects. That was 1998.

Bud will only challenge the hanford link because he cannot challenge
those 'scary pictures'. One is a Boston building fire last year
created by a plug-in protector. Another is a fire marshal describing
why plug-in protectors can create house fires. And pictures from fire
departments showing a problem seen too often.

And then Bud posts a half fact. UL1449 was created on 28 Aug 1985 -
not in 1998 as Bud claims. Why would Bud do this? Profits are at
risk - another fact that Bud must avoid admitting.

So where is this plug-in protector spec that claims to provide
protection? Oh. It does not exist because plug-in protectors do not
even claim to provide this protection. Bud refuses to post a
specification for one simple reason. There is no plug-in spec that
claims what Bud is posting. So Bud posts insults. In reply, this is
what Bud is really promoting - these 'scary pictures':
http://www.hanford.gov/rl/?page=556&parent=554
http://www.westwhitelandfire.com/Articles/Surge Protectors.pdf
http://www.ddxg.net/old/surge_protectors.htm
http://www.zerosurge.com/HTML/movs.html
http://tinyurl.com/3x73ol or
http://www3.cw56.com/news/articles/local/BO63312/

Pictures of protectors typically located on a pile of desktop papers
or buried in dust balls on a rug.

 

[w_tom]

I suppose I phrased the question badly. I wonder why a surge
would wander around looking for ground, when its available
in the box!

If all grounds are same, then connect lightning rods into a
motherboard ground. That would be perfect building protection because
a lightning rod is grounded?

Ground inside a stereo is different from ground inside a TV is
different from ground on the computer case is different from ground on
a wall receptacle is different from ground inside a cell phone is
different from a ground inside a breaker box is different from ground
in earth. Most all those grounds are interconnected and are still not
the same ground.

Electricity is different at both ends of a wire. That 100 amp surge
seeking earth from a wall receptacle may leave the wall receptacles at
12,000 volts - again, due to wire impedance. That plug-in protector
on Page 42 Figure 8 was so far from earth ground (via AC electric
wire) as to be >8000 volts - a destructive path via an adjacent TV to
earth.

The EE Times article entitled "Protecting Electrical Devices from
Lightning Transients" defines why a ground in a box is not a ground to
surges. Why electricity at both ends of a wire is always different.
Why that difference during a surge is so important that an effective
protection makes a 'less than 10 foot' connection to earth. Only
relevant 'ground' is the one that is ground to a surge. That is not
an 'inside the box' ground.

Typically destructive surges are an electrical connection from a
cloud to earthborne charges maybe miles away - the relevant ground.
If any part of that connection is via an appliance, then the appliance
may be damaged. Surge protection has always been about diverting a
connection from cloud to earthborne charges so that current need not
pass inside the building.

A protector is only as effective as its earth ground so that surges
need not enter a building. No earth ground means no effective
protection; means a surge creates connections to earth destructively
inside a building. Any facility that installs effective protection
does earthing connected, very short, via a 'whole house' type
protector.

Polyphaser makes a protector that has NO earth ground connection.
Earthing is so critical that their protector mounts directly ON the
earthing electrode - zero feet from earth ground. Distance to earth
ground is critical for effective protection. Which ground? Earth
ground is not found and not provide in three wire AC wall
receptacles. That is a safety ground.

 

[w_tom]

Where did I say HOW was protected? It was my second week at that
station, and the chief engineer took off on a long overdue vacation. If
you would learn to read, rather than just do mindless rants you wouldn't
look so stupid. At that time the building had a UFER ground, and a
three phase protection system at the meter CTs. That didn't prevent the
damage, as you claim it should.

Lightning created damage. Since Michael Terrell says it had an Ufer
ground, that means grounding was properly installed and not
corrupted? Therefore the resulting damage proves, "Woe is me.
Nothing can protect from lightning."? Nonsense.

Damage was created by a surge. A responsible human locates the
defect in that protection system. Michael Terrell was defeatist. He
'knew' nothing can earthing lightning without damage.

Then Michael posts nonsense about other protectors so he need not
admit this fact: MOVs are not used on telephone lines. Why discuss
fuses? Fuses obviously are not for surge protection - when one has
basic electrical knowledge. Effective protectors (even gas discharge
tubes - GDTs) earth direct lightning strikes and remain functional.

So why is Michael now discussing GDTs and fuses? Michael has again
been caught posting in error. MOVs are not used for telephone line
surge protection due to excessive capacitance. This has long been
common knowledge among those who post facts - not insults. Nnoted and
finally admitted by Michael is a reasons why so little lightning in
the UK creates so much damage. Master sockets are not even earthed as
the equivlant NID is, routinely, in all North America.

Responsible people who suffer surge damage immediately search for
the human failure that made damage possible. Search typically begins
by looking for defects in the single point earth ground system. Those
who promote magic box plug-in protectors would not do this and must
assume lightning damage cannot be avoided - a defeatist attitude.

 

[w_tom]

W_ denies MOVs are commonly used in typical electonics or modern
appliances too. He had to, because he can't answer the obvious
question of how MOVs can be used effectively in these applications,
yet they can't work in plug-in protectors and the only way to get any
protection is to have a nearby direct earth ground. Faced with the
problem of MOVs providing protection in electronics/appliance without
an earthground, he simply denies MOVs are used in electronics and
appliances. ...

Using trader's reasoning, all appliances contain MOVs. Therefore
plug-in protectors need not be purchased AND all appliances never
suffer surge damage. Conclusions directly from trader's post.

Reality: all appliances contain protection using numerous techniques
such as galvanic isolation. Protection that means all but a rare and
typically destructive surge is made irrelevant. Internal appliance
protection is dependent on a properly earthed 'whole house'
protector. The typically destructive surge must be earthed to not
overwhelm protection inside all appliances.